FDA: Labeling Change for Leukotriene Modifiers

Leukotriene modifiers (also known as Leukotriene Receptor Antagonists) are common asthma drugs that have been rarely linked to something called Churg-Strauss syndrome (good trivia fact). The FDA has requested that certain drug manufacturers include a precaution in the drug prescribing information (drug labeling) regarding neuropsychiatric events (behavior, mood changes) that have been reported in some persons taking montelukast (Singulair), zafirlukast (Accolate), and zileuton (Zyflo and Zyflo CR).

• Singulair is manufactured by Merck.
• Accolate is manufactured by AstraZeneca
• Zyflo is manufactured by Cornerstone Therapeutics, Inc.
  

What is it about certain medications? Can we be certain that these are all drug-induced effects? If clinical studies are not designed to look for such findings, can we be confident that post-marketing data can be interpreted properly? Do these drugs really cause mood changes? Or, are these simply associations that have no causality? Pretty soon, every single prescription drug out there will have some type of black box warning about mood changes and possible suicidal behavior. Once that happens, everyone will be ignoring these warnings.